Recognition assessed by D' and by a non-parametric alternative (the A-index) as a function of the number of choices

Freedom from restrictive assumptions and ease of psychological interpretation are two basic criteria for a satisfactory measure of recognition performance. The A-index (Brown, 1965a) comes close to fulfilling these criteria. It is based on the proportion of wrong choices rejected in a multi-choice test as revealed by the number of choices required to select the correct choice. It can be transformed into the d' measure of signal detection theory (SDT) if the standard assumptions of this theory hold, but not in general. Two experiments on the recognition of words-in-noise are described. In the first there were 3, 5, 8 or 16 choices. They were typed on a card which was displayed to the listener during the presentation of a word. On both measures 5-, 8- and 16-choice recognition did not differ significantly, while 3-choice recognition was slightly, but significantly, superior. The second experiment concerned the effect of delaying the display of the card until 2 sec. after presentation. No evidence for an effect was obtained. In both experiments, there was suggestive but not conclusive evidence that the d' measure tended to overestimate recognition efficiency.     

USE OF THE GATB IN PREDICTING SUCCESS ON THE TESTS OF GENERAL EDUCATIONAL DEVELOPMENT

An attempt was made to determine how useful the General Aptitude Test Battery can be when used as a predictor of success on the Tests of General Educational Development. The General Ability and Verbal Aptitude subtests of the GATB were found to be the best predictors. Estimating the applicant's chance of passing the GED from the ‘G’ and ‘V’ scores was discussed.     

Effects of grammaticalness, presentation rate, and message length on auditory short-term memory

The aim of this study was to demonstrate the effect of message structure, message length, and presentation rate upon auditory short-term memory. Subjects were asked to reproduce in writing messages at different levels of “grammaticalness” (Coleman, 1965) presented through headphones at 3-4 words/sec. or 6-7 words/ sec. There was better recall of the more structured, shorter, and slower messages. The results are discussed in terms of acquisition and encoding of information.     

Similarity of schematic faces: A test of

In this study we obtained direct and comparative judgments of the dissimilarity between schematic faces varying on three binary attributes. These data were used to test the hypothesis that the overall dissimilarity between faces can be decomposed (in an ordinal sense) into three additive components, one for each attribute. The hypothesis was strongly confirmed by both the direct and the comparative judgments. The study illustrates the possible usefulness of the measurement-theoretic analysis of simple combination mies for psychological dimensions.     

Similarity judgments of line length

Nine Ss judged similarity of pairs of lines on a scale from 0 to 100, and 14 Ss made magnitude estimations of similarity of pairs of lines. The two scales of similarity were linearly related. Scale values for subjective length were obtained in one dimension using a nonmetric multidimensional analysis. Subjective length was found to be logarithmically related to objective length, and similarity was found to be an exponential     

Orientation of letters and errors in their recognition

Subjects named alphabetic characters that had been rotated, reflected, or inverted. Inversions induce more errors than mirror reflections and reflections induce more than rotations. In a significant number of mistakes a transformed character was assumed to be normally oriented, but in most a transformed character was confused with the mirror image of the original. The data suggest the existence of an “orientation set” in which the identiflcation of ambiguous characters depends largely on their anticipated orientation. The individuality of the data for the different orientations suggests that different transformations are compensated for in part by different mechanisms.     

Verbal interference in a perceptual comparison task

When Ss had to indicate if the colors of pairs of items from the Stroop test were the same or different, the usual interference effect was completely eliminated. However, when the verbal information consisted of SAME and DIFF rather than color names, interference was reestablished. This indicates that the perceptual comparison task does not eliminate interference simply by rendering Ss insensitive to the meanings of words.     

Experimental control of superstitious responding in humans

Superstitions were demonstrated with human subjects when presses on one button were reinforced on a VI 30-sec schedule while presses on a second were never reinforced. Superstitious responding, on the second button, was often maintained because presses on that button were frequently followed by reinforcement for a subsequent press on the first button. The introduction of a changeover delay (COD), which separated in time presses on the second button and subsequent reinforced presses on the first button, reduced or eliminated the superstitious responding of these subjects. Some complex superstitions were also demonstrated with other subjects for which the COD was in effect from the beginning of the session.     

Increased eating in rats deprived of running

Daily food intake in rats was temporarily reduced by the introduction of an activity wheel and temporarily increased by the subsequent removal of the wheel. When this outcome is coupled with the positive relation between food deprivation and running—and food deprivation is seen as a loss of eating rather than as a physiological state—there is the suggestion that the total behavior output of the organism may be regulated as such. Specifically, when the rat is deprived of a behavior that recurrently comprises a large part of its total daily activity, an increase may occur in some other behavior.     

Generalization gradients of inhibition following auditory discrimination learning

A more direct method than the usual ones for obtaining inhibitory gradients requires that the dimension of the nonreinforced stimulus selected for testing be orthogonal to the dimensions of the reinforced stimulus. In that case, the test points along the inhibitory gradient are equally distant from the reinforced stimulus. An attempt was made to realize this condition by obtaining inhibitory gradients along the frequency dimension of a pure tone after discrimination training in which the nonreinforced stimulus was a pure tone (or tones), and the reinforced stimulus was either white noise or the absence of a tone. The results showed that some degree of specific inhibitory control was exerted by the frequency of the tone, although the gradients were broad and shallow in slope.

A further experiment was conducted to see whether the modification of an excitatory gradient resulting from training to discriminate neighboring tones could arise from a simple interaction of inhibitory and excitatory gradients. The results indicated that it could not, since discrimination training produced a concentration of responding in the vicinity of the reinforced stimulus which cannot be derived from any plausible gradient of inhibition.